efi_loader: enable QueryVariableInfo at runtime for file backed variables

Since commit c28d32f946f0 ("efi_loader: conditionally enable SetvariableRT")
we are enabling the last bits of missing runtime services.
Add support for QueryVariableInfo which we already support at boottime
and we just need to mark some fucntions available at runtime and move
some checks around.

It's worth noting that pointer checks for maxmimum and remaining
variable storage aren't when we store variables on the RPMB, since the
Secure World backend is already performing them.

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

5 files changed, 39 insertions, 15 deletions

diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index 73831c5..011bcd0 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -129,6 +129,10 @@ efi_status_t efi_init_runtime_supported(void)
 				EFI_RT_SUPPORTED_SET_VIRTUAL_ADDRESS_MAP |
 				EFI_RT_SUPPORTED_CONVERT_POINTER;
 
+	if (IS_ENABLED(CONFIG_EFI_VARIABLE_FILE_STORE))
+		rt_table->runtime_services_supported |=
+			EFI_RT_SUPPORTED_QUERY_VARIABLE_INFO;
+
 	if (IS_ENABLED(CONFIG_EFI_RT_VOLATILE_STORE)) {
 		u8 s = 0;
 
diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index 961139f..ea8d2a4 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -1,4 +1,3 @@
-// SPDX-License-Identifier: GPL-2.0+
 /*
  * UEFI runtime variable services
  *
@@ -163,11 +162,6 @@ efi_status_t EFIAPI efi_query_variable_info(
 	EFI_ENTRY("%x %p %p %p", attributes, maximum_variable_storage_size,
 		  remaining_variable_storage_size, maximum_variable_size);
 
-	if (!maximum_variable_storage_size ||
-	    !remaining_variable_storage_size ||
-	    !maximum_variable_size)
-		return EFI_EXIT(EFI_INVALID_PARAMETER);
-
 	ret = efi_query_variable_info_int(attributes,
 					  maximum_variable_storage_size,
 					  remaining_variable_storage_size,
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 0cbed53..1cc02ac 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -406,12 +406,15 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
 	return EFI_SUCCESS;
 }
 
-efi_status_t efi_query_variable_info_int(u32 attributes,
-					 u64 *maximum_variable_storage_size,
-					 u64 *remaining_variable_storage_size,
-					 u64 *maximum_variable_size)
+efi_status_t __efi_runtime
+efi_query_variable_info_int(u32 attributes,
+			    u64 *maximum_variable_storage_size,
+			    u64 *remaining_variable_storage_size,
+			    u64 *maximum_variable_size)
 {
-	if (attributes == 0)
+	if (!maximum_variable_storage_size ||
+	    !remaining_variable_storage_size ||
+	    !maximum_variable_size || !attributes)
 		return EFI_INVALID_PARAMETER;
 
 	/* EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated */
@@ -460,7 +463,17 @@ static efi_status_t __efi_runtime EFIAPI efi_query_variable_info_runtime(
 			u64 *remaining_variable_storage_size,
 			u64 *maximum_variable_size)
 {
-	return EFI_UNSUPPORTED;
+	if (!(attributes & EFI_VARIABLE_RUNTIME_ACCESS))
+		return EFI_INVALID_PARAMETER;
+	if ((attributes & (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
+			   EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS |
+			   EFI_VARIABLE_ENHANCED_AUTHENTICATED_ACCESS)))
+		return EFI_UNSUPPORTED;
+
+	return efi_query_variable_info_int(attributes,
+					   maximum_variable_storage_size,
+					   remaining_variable_storage_size,
+					   maximum_variable_size);
 }
 
 /**
diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index 4f1aa29..8b6b0a3 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -873,6 +873,11 @@ efi_status_t efi_query_variable_info_int(u32 attributes,
 	efi_status_t ret;
 	u8 *comm_buf;
 
+	if (!max_variable_storage_size ||
+	    !remain_variable_storage_size ||
+	    !max_variable_size || !attributes)
+		return EFI_INVALID_PARAMETER;
+
 	payload_size = sizeof(*mm_query_info);
 	comm_buf = setup_mm_hdr((void **)&mm_query_info, payload_size,
 				SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO,
diff --git a/lib/efi_selftest/efi_selftest_variables_runtime.c b/lib/efi_selftest/efi_selftest_variables_runtime.c
index afa91be..5794a7b 100644
--- a/lib/efi_selftest/efi_selftest_variables_runtime.c
+++ b/lib/efi_selftest/efi_selftest_variables_runtime.c
@@ -60,9 +60,17 @@ static int execute(void)
 	ret = runtime->query_variable_info(EFI_VARIABLE_BOOTSERVICE_ACCESS,
 					   &max_storage, &rem_storage,
 					   &max_size);
-	if (ret != EFI_UNSUPPORTED) {
-		efi_st_error("QueryVariableInfo failed\n");
-		return EFI_ST_FAILURE;
+
+	if (IS_ENABLED(CONFIG_EFI_VARIABLE_FILE_STORE)) {
+		if (ret != EFI_SUCCESS) {
+			efi_st_error("QueryVariableInfo failed\n");
+			return EFI_ST_FAILURE;
+		}
+	} else {
+		if (ret != EFI_UNSUPPORTED) {
+			efi_st_error("QueryVariableInfo failed\n");
+			return EFI_ST_FAILURE;
+		}
 	}
 
 	ret = runtime->set_variable(u"efi_st_var0", &guid_vendor0,